Lyme Disease: By David Robles, MD, PhD


Lyme disease is a bacterial infection caused by Borrelia burgdorferi, which is transmitted by the tick Ixodes. The tick picks up the bacteria when it bites mice or deer that are infected with the bacterium. The bacteria can be transmitted to anyone bitten by an infected tick.

Lyme disease was first reported in the United States in 1977 in the town of Old Lyme, Connecticut. Lyme disease has a worldwide distribution, but it is seen most commonly in the US.

There are 3 stages of Lyme disease:

  Stage 1 is called early-localized Lyme disease. The infection has not yet spread throughout the body.
   Stage 2 is called early-disseminated Lyme disease. The bacteria have begun to spread throughout the body.
   Stage 3 is called late-disseminated Lyme disease. The bacteria have spread throughout the body.

Risk factors for Lyme disease include:

  Outside activities that increase tick exposure (for example, gardening, hiking, or hunting) in an area where Lyme disease is known to occur.
  Having a pet that may carry ticks home.



Important facts:

   A tick must be attached to your body for about a day or more to spread the bacteria to your blood.
   Many people with Lyme disease never knew they were even bit by a tick.
   Most people who are bitten by a tick do not get Lyme disease.







Symptoms

Early localized Lyme disease (stage 1) begins days or weeks after infection and includes flu-like symptoms such as, fever, chills, headache, malaise, joint pain, muscle pain and stiff neck.

The characteristic skin presentation is a "bull's eye" rash, which is a flat or slightly raised red rash at the site of the tick bite. The red rash has central clearing and can expand in size. This rash is called erythema migrans. Erythema migrans is seen in 60– 90% of patients diagnosed with the disease. Without treatment, it can last 4 weeks or more.


If Lyme disease is untreated it can spread to the brain, heart, and joints, this is Early-disseminated Lyme disease (stage 2). This may occur weeks to months after the tick bite, and may include:

   Numbness or pain in the area, paralysis or weakness in the muscles of the face, heart problems, chest pain, or shortness of breath.

Late disseminated Lyme disease (stage 3) can occur months or years after the infection. The most common symptoms are muscle and joint pain.




Exams and Tests
A blood test can be done to check for antibodies to the bacteria that cause Lyme disease. The most commonly used is the ELISA for Lyme disease.

Treatment

A 10 day to 4-week course of doxycycline antibiotics is used to treat Lyme disease in adults and Amoxicillin is generally used in children less than 8 years of age or in pregnant women.  

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